[PATCHv3 6/11] HWMON: Support of fixed point conversion for battemperature

From: Ashish Jangam
Date: Thu May 26 2011 - 08:20:43 EST

Hi Guenter,

Existing fixed point conversion logic is modified to support battery temperature. This modified logic was compiled, linked & tested successfully.

Signed-off-by: Ashish Jangam <ashish.jangam@xxxxxxxxxxxxxxx>
Signed-off-by: David Dajun Chen <dchen@xxxxxxxxxxx>
--
diff --git a/Documentation/hwmon/da9052 b/Documentation/hwmon/da9052
new file mode 100755
index 0000000..aab7318
--- /dev/null
+++ b/Documentation/hwmon/da9052
@@ -0,0 +1,61 @@
+Kernel driver da9052-hwmon
+==========================
+
+Supported chips:
+ * Dialog Semiconductors DA9052 PMICs
+ Prefix: 'da9052'
+ Datasheet: Kindly visit www.dialog-semiconductor.com and request for the
+ official datasheet.
+
+Authors: David Dajun Chen <dchen@xxxxxxxxxxx>
+
+Description
+-----------
+
+The DA9052 provides an Analogue to Digital Converter (ADC) with 10 bits
+resolution and track and hold circuitry combined with an analogue input
+multiplexer. The analogue input multiplexer will allow conversion of up to 10
+different inputs. The track and hold circuit ensures stable input voltages at
+the input of the ADC during the conversion.
+
+The ADC is used to measure the following inputs:
+Channel 0: VDDOUT - measurement of the system voltage
+Channel 1: ICH - internal battery charger current measurement
+Channel 2: TBAT - output from the battery NTC
+Channel 3: VBAT - measurement of the battery voltage
+Channel 4: ADC_IN4 - high impedance input (0 - 2.5V)
+Channel 5: ADC_IN5 - high impedance input (0 - 2.5V)
+Channel 6: ADC_IN6 - high impedance input (0 - 2.5V)
+Channel 7: XY - TSI interface to measure the X and Y voltage of the touch
+screen resistive potentiometers
+Channel 8: Internal Tjunc. - sense (internal temp. sensor)
+Channel 9: VBBAT - measurement of the backup battery voltage
+
+By using sysfs attributes we can measure the system voltage VDDOUT, the battery
+charging current ICH, battery temperature TBAT, battery junction temperature
+TJUNC, battery voltage VBAT and the back up battery voltage VBBAT.
+
+Voltage Monitoring
+------------------
+
+Voltages are sampled by a 10 bit ADC. Voltages in millivolts are 1.465
+times the ADC value.
+
+Temperature Monitoring
+----------------------
+
+Temperatures are sampled by a 10 bit ADC. Junction and battery temperatures
+are monitored by the ADC channels.
+
+The junction temperature is calculated:
+ Degrees celsius = 1.708 * (TJUNC_RES - T_OFFSET) - 108.8
+The junction temperature attribute is supported by the driver.
+
+The battery temperature is calculated:
+ Degree Celcius = 1 / (t1 + 1/298)- 273
+where t1 = (1/B)* ln(( ADCval * 2.5)/(R25*ITBAT*255))
+Default values of R25, B, ITBAT are 10e3, 3380 and 50e-6 respectively.
+As the battery temperature computation depends on floating point
+computation and taking natural log the battery temperature attribute is
+not supported by the driver.
+
diff --git a/drivers/hwmon/Kconfig b/drivers/hwmon/Kconfig
index 3236a45..da5ff6d 100644
--- a/drivers/hwmon/Kconfig
+++ b/drivers/hwmon/Kconfig
@@ -303,6 +303,16 @@ config SENSORS_DS1621
This driver can also be built as a module. If so, the module
will be called ds1621.

+config SENSORS_DA9052_ADC
+ tristate "Dialog DA9052 HWMON"
+ depends on PMIC_DA9052
+ help
+ Say y here to support the ADC found on
+ Dialog Semiconductor DA9052 PMIC.
+
+ This driver can also be built as module. If so, the module
+ will be called da9052-hwmon.
+
config SENSORS_I5K_AMB
tristate "FB-DIMM AMB temperature sensor on Intel 5000 series chipsets"
depends on PCI && EXPERIMENTAL
diff --git a/drivers/hwmon/Makefile b/drivers/hwmon/Makefile
index f7c0c28..88b81ca 100644
--- a/drivers/hwmon/Makefile
+++ b/drivers/hwmon/Makefile
@@ -42,6 +42,7 @@ obj-$(CONFIG_SENSORS_ASC7621) += asc7621.o
obj-$(CONFIG_SENSORS_ATXP1) += atxp1.o
obj-$(CONFIG_SENSORS_CORETEMP) += coretemp.o
obj-$(CONFIG_SENSORS_PKGTEMP) += pkgtemp.o
+obj-$(CONFIG_SENSORS_DA9052_ADC) += da9052-hwmon.o
obj-$(CONFIG_SENSORS_DME1737) += dme1737.o
obj-$(CONFIG_SENSORS_DS620) += ds620.o
obj-$(CONFIG_SENSORS_DS1621) += ds1621.o
diff --git a/drivers/hwmon/da9052-hwmon.c b/drivers/hwmon/da9052-hwmon.c
new file mode 100755
index 0000000..f961d0b
--- /dev/null
+++ b/drivers/hwmon/da9052-hwmon.c
@@ -0,0 +1,379 @@
+/*
+ * HWMON Driver for Dialog DA9052
+ *
+ * Copyright(c) 2011 Dialog Semiconductor Ltd.
+ *
+ * Author: David Dajun Chen <dchen@xxxxxxxxxxx>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the
+ * Free Software Foundation; either version 2 of the License, or (at your
+ * option) any later version.
+ *
+ */
+
+#include <linux/delay.h>
+#include <linux/err.h>
+#include <linux/hwmon.h>
+#include <linux/hwmon-sysfs.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/log2.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/platform_device.h>
+#include <linux/mfd/da9052/da9052.h>
+#include <linux/mfd/da9052/reg.h>
+
+struct da9052_hwmon {
+ struct da9052 *da9052;
+ struct device *class_device;
+ struct mutex hwmon_lock;
+};
+static const char * const input_names[] = {
+ [DA9052_ADC_VDDOUT] = "VDDOUT",
+ [DA9052_ADC_ICH] = "CHARGING CURRENT",
+ [DA9052_ADC_TBAT] = "BATTERY TEMP",
+ [DA9052_ADC_VBAT] = "BATTERY VOLTAGE",
+ [DA9052_ADC_IN4] = "ADC IN4",
+ [DA9052_ADC_IN5] = "ADC IN5",
+ [DA9052_ADC_IN6] = "ADC IN6",
+ [DA9052_ADC_TJUNC] = "BATTERY JUNCTION TEMP",
+ [DA9052_ADC_VBBAT] = "BACK-UP BATTERY VOLTAGE",
+};
+
+static int da9052_enable_vddout_channel(struct da9052 *da9052)
+{
+ int ret;
+
+ ret = da9052_reg_read(da9052, DA9052_ADC_CONT_REG);
+ if (ret < 0)
+ return ret;
+
+ ret |= DA9052_ADCCONT_AUTOVDDEN;
+ return da9052_reg_write(da9052, DA9052_ADC_CONT_REG, ret);
+}
+
+static int da9052_disable_vddout_channel(struct da9052 *da9052)
+{
+ int ret;
+
+ ret = da9052_reg_read(da9052, DA9052_ADC_CONT_REG);
+ if (ret < 0)
+ return ret;
+
+ ret &= ~DA9052_ADCCONT_AUTOVDDEN;
+ return da9052_reg_write(da9052, DA9052_ADC_CONT_REG, ret);
+
+}
+
+static ssize_t da9052_read_vddout(struct device *dev,
+ struct device_attribute *devattr, char *buf)
+{
+ struct da9052_hwmon *hwmon = dev_get_drvdata(dev);
+ int ret;
+ int vdd = -1;
+
+ mutex_lock(&hwmon->hwmon_lock);
+
+ ret = da9052_enable_vddout_channel(hwmon->da9052);
+ if (ret < 0)
+ goto hwmon_err;
+
+ ret = da9052_reg_read(hwmon->da9052, DA9052_VDD_RES_REG);
+ if (ret < 0)
+ pr_err("failed to read VDD_RES_REG\n");
+ else
+ vdd = ret;
+
+ ret = da9052_disable_vddout_channel(hwmon->da9052);
+ if (ret < 0)
+ goto hwmon_err;
+
+ if (vdd) {
+ mutex_unlock(&hwmon->hwmon_lock);
+ return sprintf(buf, "%d\n", vdd);
+ }
+hwmon_err:
+ mutex_unlock(&hwmon->hwmon_lock);
+ return ret;
+}
+
+static ssize_t da9052_read_ich(struct device *dev,
+ struct device_attribute *devattr, char *buf)
+{
+ struct da9052_hwmon *hwmon = dev_get_drvdata(dev);
+ int ret;
+
+ ret = da9052_reg_read(hwmon->da9052, DA9052_ICHG_AV_REG);
+ if (ret < 0)
+ return ret;
+
+ /* Equivalent to 3.9mA/bit in register ICHG_AV */
+ ret = DIV_ROUND_CLOSEST(ret * 39, 10);
+ return sprintf(buf, "%d\n", ret);
+}
+
+#define BCONST 3
+#define TBAT 3355705
+#define CAL_LOG2(nr) ((int)((ilog2(nr) - ilog2(100)) * 693147181LL))
+/*
+ The battery temperature is calculated:
+ Degree Celcius = 1 / (t1 + 1/298)- 273
+ where t1 = (1/B)* ln((ADCval * 2.5)/(R25*ITBAT*255))
+ And R25 = 10e3, B = 3380 and ITBAT = 50e-6
+*/
+static int cal_temperature(int adc_val)
+{
+
+ int log_val;
+ unsigned int temp, deg_celcius;
+
+ /* Formula 2.5/(R25*ITBAT*255) gets reduced to 0.02
+ Convert float value to fixed point using a multiplier */
+ log_val = adc_val * 2;
+
+ temp = BCONST * (CAL_LOG2(log_val) * 10000) + TBAT;
+
+ /* ln(x) = log2(x) * ln(2) = log2(x) * 0.693147181
+ log2(float) is converted to fixed point as log2(nr) - log2(dr) */
+ deg_celcius = ((1000000000/temp) - 273);
+
+ /* Battery temperature in degree celcius */
+ return deg_celcius;
+}
+
+static ssize_t da9052_read_tbat(struct device *dev,
+ struct device_attribute *devattr, char *buf)
+{
+ struct da9052_hwmon *hwmon = dev_get_drvdata(dev);
+ int ret;
+ int tbat;
+
+ ret = da9052_reg_read(hwmon->da9052, DA9052_TBAT_RES_REG);
+ if (ret < 0)
+ return ret;
+
+ tbat = cal_temperature(ret);
+
+ return sprintf(buf, "%d\n", (tbat*1000));
+}
+
+static ssize_t da9052_read_vbat(struct device *dev,
+ struct device_attribute *devattr, char *buf)
+{
+ struct da9052_hwmon *hwmon = dev_get_drvdata(dev);
+ int ret;
+
+ ret = da9052_adc_manual_read(hwmon->da9052, DA9052_ADC_VBAT);
+ if (ret < 0)
+ return ret;
+
+ return sprintf(buf, "%d\n", ret);
+}
+
+static ssize_t da9052_read_misc_channel(struct device *dev,
+ struct device_attribute *devattr, char *buf)
+{
+ struct da9052_hwmon *hwmon = dev_get_drvdata(dev);
+ int channel = to_sensor_dev_attr(devattr)->index;
+ int ret;
+
+ ret = da9052_adc_manual_read(hwmon->da9052, channel);
+ if (ret < 0)
+ return ret;
+
+ return sprintf(buf, "%d\n", ret);
+}
+
+static ssize_t da9052_read_tjunc(struct device *dev,
+ struct device_attribute *devattr, char *buf)
+{
+ struct da9052_hwmon *hwmon = dev_get_drvdata(dev);
+ int temp;
+ int ret;
+
+ ret = da9052_reg_read(hwmon->da9052, DA9052_TJUNC_RES_REG);
+ if (ret < 0)
+ return ret;
+
+ temp = ret;
+
+ ret = da9052_reg_read(hwmon->da9052, DA9052_T_OFFSET_REG);
+ if (ret < 0)
+ return ret;
+
+ /* Degrees celsius = 1.708 * (TJUNC_RES - T_OFFSET) - 108.8 */
+ ret = 1708 * (temp - ret) - 108800;
+ return sprintf(buf, "%d\n", ret);
+}
+
+static ssize_t da9052_read_vbbat(struct device *dev,
+ struct device_attribute *devattr, char *buf)
+{
+ struct da9052_hwmon *hwmon = dev_get_drvdata(dev);
+ int ret;
+
+ ret = da9052_adc_manual_read(hwmon->da9052, DA9052_ADC_VBBAT);
+ if (ret < 0)
+ return ret;
+
+ return sprintf(buf, "%d\n", ret);
+
+}
+
+static ssize_t da9052_hwmon_show_name(struct device *dev,
+ struct device_attribute *devattr, char *buf)
+{
+ return sprintf(buf, "da9052-hwmon\n");
+}
+
+static ssize_t show_label(struct device *dev,
+ struct device_attribute *devattr, char *buf)
+{
+ return sprintf(buf, "%s\n",
+ input_names[to_sensor_dev_attr(devattr)->index]);
+}
+
+static SENSOR_DEVICE_ATTR(in0_input, S_IRUGO, da9052_read_vddout, NULL,
+ DA9052_ADC_ICH);
+static SENSOR_DEVICE_ATTR(in0_label, S_IRUGO, show_label, NULL,
+ DA9052_ADC_ICH);
+static SENSOR_DEVICE_ATTR(in3_input, S_IRUGO, da9052_read_vbat, NULL,
+ DA9052_ADC_VBAT);
+static SENSOR_DEVICE_ATTR(in3_label, S_IRUGO, show_label, NULL,
+ DA9052_ADC_VBAT);
+static SENSOR_DEVICE_ATTR(in4_input, S_IRUGO, da9052_read_misc_channel, NULL,
+ DA9052_ADC_IN4);
+static SENSOR_DEVICE_ATTR(in4_label, S_IRUGO, show_label, NULL,
+ DA9052_ADC_IN4);
+static SENSOR_DEVICE_ATTR(in5_input, S_IRUGO, da9052_read_misc_channel, NULL,
+ DA9052_ADC_IN5);
+static SENSOR_DEVICE_ATTR(in5_label, S_IRUGO, show_label, NULL,
+ DA9052_ADC_IN5);
+static SENSOR_DEVICE_ATTR(in6_input, S_IRUGO, da9052_read_misc_channel, NULL,
+ DA9052_ADC_IN6);
+static SENSOR_DEVICE_ATTR(in6_label, S_IRUGO, show_label, NULL,
+ DA9052_ADC_IN6);
+static SENSOR_DEVICE_ATTR(in9_input, S_IRUGO, da9052_read_vbbat, NULL,
+ DA9052_ADC_VBBAT);
+static SENSOR_DEVICE_ATTR(in9_label, S_IRUGO, show_label, NULL,
+ DA9052_ADC_VBBAT);
+static SENSOR_DEVICE_ATTR(curr1_input, S_IRUGO, da9052_read_ich, NULL,
+ DA9052_ADC_ICH);
+static SENSOR_DEVICE_ATTR(curr1_label, S_IRUGO, show_label, NULL,
+ DA9052_ADC_ICH);
+
+static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, da9052_read_tbat, NULL,
+ DA9052_ADC_TBAT);
+static SENSOR_DEVICE_ATTR(temp1_label, S_IRUGO, show_label, NULL,
+ DA9052_ADC_TBAT);
+
+static SENSOR_DEVICE_ATTR(temp2_input, S_IRUGO, da9052_read_tjunc, NULL,
+ DA9052_ADC_TJUNC);
+static SENSOR_DEVICE_ATTR(temp2_label, S_IRUGO, show_label, NULL,
+ DA9052_ADC_TJUNC);
+
+static DEVICE_ATTR(name, S_IRUGO, da9052_hwmon_show_name, NULL);
+
+static struct attribute *da9052_attr[] = {
+ &dev_attr_name.attr,
+
+ &sensor_dev_attr_in0_input.dev_attr.attr,
+ &sensor_dev_attr_in0_label.dev_attr.attr,
+ &sensor_dev_attr_curr1_input.dev_attr.attr,
+ &sensor_dev_attr_curr1_label.dev_attr.attr,
+ &sensor_dev_attr_temp1_input.dev_attr.attr,
+ &sensor_dev_attr_temp1_label.dev_attr.attr,
+ &sensor_dev_attr_in3_input.dev_attr.attr,
+ &sensor_dev_attr_in3_label.dev_attr.attr,
+ &sensor_dev_attr_in4_input.dev_attr.attr,
+ &sensor_dev_attr_in4_label.dev_attr.attr,
+ &sensor_dev_attr_in5_input.dev_attr.attr,
+ &sensor_dev_attr_in5_label.dev_attr.attr,
+ &sensor_dev_attr_in6_input.dev_attr.attr,
+ &sensor_dev_attr_in6_label.dev_attr.attr,
+ &sensor_dev_attr_temp1_input.dev_attr.attr,
+ &sensor_dev_attr_temp1_label.dev_attr.attr,
+ &sensor_dev_attr_temp2_input.dev_attr.attr,
+ &sensor_dev_attr_temp2_label.dev_attr.attr,
+ &sensor_dev_attr_in9_input.dev_attr.attr,
+ &sensor_dev_attr_in9_label.dev_attr.attr,
+ NULL
+};
+
+static const struct attribute_group da9052_attr_group = {.attrs = da9052_attr};
+
+static int __init da9052_hwmon_probe(struct platform_device *pdev)
+{
+ struct da9052_hwmon *hwmon;
+ int ret;
+
+ hwmon = kzalloc(sizeof(struct da9052_hwmon), GFP_KERNEL);
+ if (!hwmon)
+ return -ENOMEM;
+
+ mutex_init(&hwmon->hwmon_lock);
+ hwmon->da9052 = dev_get_drvdata(pdev->dev.parent);
+
+ platform_set_drvdata(pdev, hwmon);
+
+ ret = sysfs_create_group(&pdev->dev.kobj, &da9052_attr_group);
+ if (ret)
+ goto err_mem;
+
+ hwmon->class_device = hwmon_device_register(&pdev->dev);
+ if (IS_ERR(hwmon->class_device)) {
+ ret = PTR_ERR(hwmon->class_device);
+ sysfs_remove_group(&pdev->dev.kobj, &da9052_attr_group);
+ goto err_mem;
+ }
+
+ return 0;
+
+err_mem:
+ kfree(hwmon);
+ return ret;
+}
+
+static int __devexit da9052_hwmon_remove(struct platform_device *pdev)
+{
+ struct da9052_hwmon *hwmon = platform_get_drvdata(pdev);
+
+ hwmon_device_unregister(hwmon->class_device);
+ sysfs_remove_group(&pdev->dev.kobj, &da9052_attr_group);
+ mutex_destroy(&hwmon->hwmon_lock);
+ kfree(hwmon);
+
+ return 0;
+}
+
+static struct platform_driver da9052_hwmon_driver = {
+ .driver = {
+ .name = "da9052-hwmon",
+ .owner = THIS_MODULE,
+ },
+ .probe = da9052_hwmon_probe,
+ .remove = __devexit_p(da9052_hwmon_remove),
+
+};
+
+static int __init da9052_hwmon_init(void)
+{
+
+ return platform_driver_register(&da9052_hwmon_driver);
+}
+module_init(da9052_hwmon_init);
+
+static void __exit da9052_hwmon_exit(void)
+{
+ platform_driver_unregister(&da9052_hwmon_driver);
+}
+module_exit(da9052_hwmon_exit);
+
+MODULE_AUTHOR("David Dajun Chen <dchen@xxxxxxxxxxx>");
+MODULE_DESCRIPTION("DA9052 HWMON driver");
+MODULE_LICENSE("GPL v2");
+MODULE_ALIAS("platform:da9052-hwmon");


Regards,
Ashish


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